Brake



Sept. 1, 1931.

E. W. SEAHOLM ET AL BRAKE Original Filed Feb. 13, 1924 T m H Y We w E M m NE O FIDKS v m M m P f M N RwR j EGA 7 Z; Z6 6 32 a 4 ,1 /7 I/ 2 \w w M. a M RM MM. 2% flfiq.

Z w o o M Paw a w Patented Sept. 1, 1931 f UNITED STATES PATENT OFFICE ERNEST W. SEAHOLM, GUY E. PARKER, AND ARTHUR H. STAHLHUTH, OF DETROIT,

MICHIGAN, ASSIGNORS TO BENDIX BRAKB.COMPANY, CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS BRAKE Original application filed February 13, 1924, Serial No. 692,526. Divided and this -0otober. 1, 1926. Serial No. 138,837.

This invention relates to brakes of the servo or booster type and is illustrated aserable for use inassociation with brake devices applied to the front wheel of the road vehicle and which will not interfere in any way with the free swirling or turning movement of such wheel or its associated parts.

I In one desirable embodiment the brake mechanism comprises a pair of oppositely movable brake members arranged on opposite sides of the king pin which swivels on the wheel supporting knuckles of the axle and a servo device arranged between the free ends of said members above the king pin and connections betweenthe servo device and the brake members operable to move said mem-' bers into engagement with the brake drum upon circum erential movement of said servo devices produced by its engagement with the brake drum, all of which operations are capable of being accomplished without inter fering with the swiveling movement of the,

' right angles to the view in Fig. 1 and showing the steering knuckle and a fragment of the front axle inelevation.

Let 14 indicate the front wheel journaled on a steering knuckle 16 which is swiveled to the front axle 18 by a king-pin 20. The front wheel carries a drum 22 within which-brake shoes 24 and 26 are disposed These brake shoes accomplish the major portion of the braking action Each shoe is anchored at the bottom. It is provided with a substantially application filed.

rectangular slot which is slidably mounted upon a block 28, which block is j onrnaled on a stub shaft 30 supported by a bracket 32 which bracket is integral with or secured to the dust plate 34 that is carried by the axle 12 or the knuckle 16.

These two shoes extend on opposite sides of the king-pin 20 and the upper ends are free and spaced apart. Servo operating mechanism is disposed between the free ends of these shoes to urge them. outwardly against the brake drum.

The anchored ends of the shoes are urged away from the drum by return spring 36. This movement is limited by stops 38 which stops are adjustably threaded into arms carried by the brackets 32'. The free end of each shoe is urged'away from the drum by a spring 40 as far as permitted by a stop 42 adjustably threaded into the shoe and adapted to engage a bracket 44 carried by the plate 34. It has been found convenient to attach thereturn springs 36 and 40 to the-brackets 44. The shoes areheld' against lateral displacement 1 at the anchored ends by the brackets 32 and washers 46, and are held against lateral displacement at their free ends by sliding engagement with the arms of U-shaped stamp- .in'gs 48 carried by the plate 34. The 'shoes 24 and 26 are spread apart against the drum by servo mechanism comprising a servo or booster shoe 66 floated between the free ends of the shoes 24 and 26 and having a permitted circumferential movement when in frictional engagement with the drum 22. A rock lever 58 is coupled with the servo shoe to be actuated thereby and has a spherical head 64 which is engaged by a suitable part on said ice with a pairof semicylindrical recesses which engage rollers 54 and 56 mounted on the brake operating lever 58. The member is provided with corresponding semicylindrical recesses engaging thesame rollers and with a rectangular slot embracing a roller 60 supported by an eccentric carried by a bracket riveted to plate 34, the eccentric permitting adjustment of the vertical position of the various parts. Circumferential movement of the servo shoe serves to rock the lever 58 in one direction or the other and spread the shoes 24 and 26 apart through the medium of members 50 and 52. V i

The servo shoe is provided at a point intermediate its ends with a pair of parallel guide lugs 72 between which is arranged a bearing plate 74 of hardened material. which bearing plate is engaged by a cam link member 76 which has rolling engagement therewith and which is positioned with respect thereto by a cross pin 78 which enters notches in the guide lugs 72. The member 76 is pivotally sup-.

ported on a crank pin 80 which is actuated by an arm 86 through a telescoping rock shaft 88 that has a universal joint above the king pin 20 and which is supported by a universal joint on the chassis frame 90. As explained in application S. N. 674,235, filed November 12, 1923, by E. W. Seaholm, the connections 86, 88, 80; and 82 operate to release the'brake automatically in rounding a corner to guard against the possibilitv of loss of steering control by virtue of locking the wheels.

In operation. manipulation of the arm 86 by the driver through the usual connections moves the member 76 radially outward against the resistance of spring and pressesthe servo shoe 66 against the drum. If the drum is turning in either direction, the servo shoe is 'frictionally urged circumferentially 1n the same direction and moves more or less according to the force supplied bv the driver, thereby rocking the lever 58 and forcing the shoes 24 and 26against the drum. Advantage is thus taken of the momentum of the vehicle to apply the brakes with great force with comparatively little exertion on the part of the driver. The servo shoe 66 is supported by rolling engagement with roller 68 and member 76. Member 76 may have this servo engaging surface concentric with the crank pin 80; to guard against any possibility of grabbing, this surface may have its axis slightly above the axis of the crank pin, so that as the servo shoe moves circumferentially, the pressure on it is slightly relieved, or

else it becomes necessary further to depress.

the brake pedalor its equivalent.

While one illustrative embodiment of our invention has been described in detail, it is not our intention to limit the scope of the inventlon to such embodiment or otherwise than by the terms of the claims.

What is claimed is:

1. Afront wheel brake comprising, in combination, a front axle, a knuckle, a king pin connecting the knckle and axle, a wheel journaled on the knuckle and having a brake. drum substantially encircling the kingpin, retarding means supported by the knuckle in operative proximity to the drum includi a servo device arranged within the space fietween the top' of the king pin and the inner periphery of the drum, and driver-controlled means for operating the servo device which constructed and arranged to permit swivel- '1ng movement of the knuckle and wheel about joint within the axis of and above the king pin and having a part extending therefrom and coupled with the servo device in the space between the end of the king pin and said device.

3. In a road vehicle, a swiveled front wheel,

a brake drum on the wheel, brake mechanism within the drum comprising retarding members adapted to be moved into frictional engagement with the drum and a servo device positioned between such retarding members and within the space between one end of the swiveled support for the wheel and the inner periphery of the drum and an actuator for the servo device comprising a rotatable member having bearing engagement with substantially the central portion of the device and having a universal joint in alignment with the swiveling axis.

4. Brake mechanism for-a road vehicle, comprising in combination, a front axle, a knuckle, a wheel journaled on the knuckle, a king pin connecting the knuckle with the axle, a brake drum on the wheel, a backing plate carried by the knuckle, brake members within the drum, a servo shoe arranged to float within the space between the upper end of the king pin and the inner periphery of the drum, and an operating connection having a part extending through the backing plate and provided with a universal joint posi tioned outside the drum and in the axis of the king pin.

5.. In a road vehicle, a front axle, a knuckle, a king pin, a wheel on the knuckle, a brake drum onthe wheel, a pair of brake members within the drum one on each side of the king pin, each member anchored below the king pin against circumferential movement but having a permitted radial movement, the opposite free ends of said members being spaced apart above the king pin, a floating shoe located between the free ends of said members, and within the space between the upper end of the king pin and the inner periphery of the drum, means coupling the floating shoe with said members to translate the circumferential movement of the floating shoe into radial movement of said members and means arranged between the top of said king pin and said floating shoe to move the shoe again st the drum.

6. In a road vehicle a front wheel brake comprising in combination a front axle, a knuckle, a king pin connecting the knuckle with the axle, a wheel journaled on the knuckle, a brake drum on the wheel, a backing plate carried by the knuckle, retarding means within the drum comprising a pair of brake members one positioned on each side of the king pin and a servo device positioned within the space between one end of the king pin and the drum and between the said brake members, means for actuating said servo de-,

vice radially into frictional engagement with the drum, comprising a shaft extending rotatably through the backing plate and terminating within the drum in a radially extending part operatively engaging the servo and positioned within the space between the drum and the end of the "king pin and provided on the opposite side of thebacking plate with a universal joint positioned in the axis of rotation of the king pin. 7. A front wheel brake comprising, in combination, a front axle,.a knuckle swivelled thereto, a wheel journalled on the knuckle, a.

brake drum carried by the wheel,.retarding means supported by the knuckle in operative proximity to the drum including a servo device arranged at one end and slightly offset the swivelling axis of the wheel, operating means connected therewith having a universal joint located in said swivelling axis, and an actuator connected to and in alignment with the universal joint for bearing engagement with the servo device.

8. In a road vehicle, afront axle having a knuckle swivelled thereon by a king pin, a wheel journalled on the knuckle, a brake drum on the wheel, brake members within the drum arranged on opposite sides of the king pin, a servo device arranged between opposite ends of' said brake members comprising a shoe supported to float within the space between said king pin and the inner 9. Brake mechanism for a wheel supported upon a swivelling axis and having a brake drum encircling said axis comprising, in com bination, brake friction means within the drum anchored beyond the lower end of said swivellin g axis and extending upwardly upon opposite sides thereof and having spaced apart ends arranged on opposite ends of the upper end of said swivelling axis, a servo of said swivelling axis and the servo device and having a universal joint located substantially in line with said swivelling axis.

In testimony whereof," we, sign this specification.

ERNEST W. SEAHOLM. GUY E. PARKER. ARTHUR H. STAHLHUTH.

periphery of the drum and between the ends member located in the. swivelling axis of said king pin. 

